Tire pressure gauge



May 13, 1952 H. w. KROHN, JR 2,596,856

I TIRE PRESSURE GAUGE l V Filedov. 29, 1949 l INVENTOR. /Mwy W /fiof/NJ?fk5 Bywfv Arme/vs ys Patented May 13, 1952 frias PRESSURE GAUGE Harry W.Krohn, Jr., Cleveland, Ohio, assignor to The Dill Manufacturing Company,Cleveland, Ohio, a corporation of Ohio Application November 29, 1949,Serial No. 129,885

1 Claim. (Cl. 7S- 419) This invention relates to a gauge for measuringair pressures in inflatable containers as, for example, the airpressures in the pneumatic tires of a motor vehicle.

An object of the invention is to provide an air gauge which is extremelysimple in design and is constructed of relatively few parts that areeasy and inexpensive to manufacture and assemble.

A further object is to provide an air gauge which is so inexpensive thatit can be sold as a novelty item to be distributed as an advertisingmedium to car owners and is of such convenient size and simplicity as tobe readily used by the car owners and carried by them either in theircars or on their persons.

A still further object is to provide an air gauge as referred to in thepreceding objects and which includes a novel chuck construction forapply- ,ing the gauge to the valve stem of an inflatable article such asa pneumatic tire.

Further and additional objects and advantages not hereinbefore referredto will become apparent hereinafter during the detailed description ofan embodiment of the invention which is to follow.

Referring to the accompanying drawing illustrating such embodiment ofthe invention,

Fig. 1 is a longitudinal sectional view through the air gauge and istaken substantially on line -I-I of Fig. 2 looking in the direction ofthe arrows.

Fig. 2 is an end view of the air gauge shown in Fig. 1 and is takenlooking at the upper end of the gauge as shown in the drawing.

l Fig. 3 is an end view of the gauge shown in Fig. 1 and is takenlooking at the lower end of the gauge as viewed in the drawing, and

Figs. 4 and 5 are transverse sectional views through the gauge and aretaken, respectively, on lines 4-4 and 5-5 of Fig. 1 looking in thedirection of the arrows.

The gauge shown in the drawing comprises an elongated cylindrical casingI of relatively small cross-sectional diameter comparable to thecross-sectional diameter of the usual pencil. The casing I0 may beformed of metal, plastic or any other suitable material for the purpose.In Fig. 1 the casing Ill is shown as provided on its exterior withcircular grooves II to form a roughened surface portion which can begripped by the gauge user to facilitate the application of the gauge toa valve stem.

The upper end of the gauge, as viewed in Fig. 1, includes a guide plugl2 mounted in the casing 2 Iii with a tight or forcedt and having at oneend a short extended circular boss I3 which projects a short distancebeyond the end of the casing. The said one end of the casing is turnedor flanged inwardly over the guide plug I2 as indicated at I4 topositively retain the plug in proper position in the casing. The plug I2is provided with a central bore therethrough which slidably mounts thegauge bar I5 that is shown as circular in cross-section, in thisinstance, and which carries suitable graduation marks and indiciacalibrated in air pounds pressure. The plug member I2 adjacent its innerend is provided with a counterbore I6 concentric with the guide borethrough the plug member and said counterbore I6 may mount a suitablefriction element I1 which frictionally grips the gauge bar and acts tohold the gauge bar in the position to which it has been extended by airpressure during the use of the gauge so that the user can take a gaugereading. Of course the element I'I could be omitted, and further thegauge bar could be arranged to return to its normal position underspring load as soon as the gauge is disconnected from the valve stem. Attheinner end of the plug member I2 there is mounted in xed position awasher I8 acting as an abutment for one end of a coil spring I9 mountedin the casing and later to be referred to.

The gauge further includes a gaugepiston consisting of a piston rodportion 20 in axial alignment with the gauge bar I5 and shown ascircular in cross-section and substantially of the same diameter as thegauge bar I5. The piston rod 20 mounts a flange or washer 2I which maybe integral with orsecured to the rod in any suitable manner and a head22 likewise secured to the rod in any suitable manner. The head 22clamps between it and the washer 2| a flexible cup-shaped piston.packing 23 whichisealingly and slidably engages the inner wall of thecasing IU. Thecoil spring I9 previously referred to surrounds the gaugebar I5 and the piston rod 20 and, as already stated, one end abuts thewasher I8 while the other end of the spring abuts the washer 2| of thepiston. It will thus be seen that movement of the piston under airpressures is resisted by the spring I9 and the strength of this springwill be calibrated in relation to the air pressures to which the pistonwill be subjected.

It will also be noted that the movement of the piston by air pressuresapplied thereto will cause the piston rod 20 to engage the end of thegauge bar I5 so that the latter will move with the piston and thus givereadings of the air pressures to which the piston is subjected. When thegauge is removed from the valve stem the spring I9 will act on thepiston to return it to its normal position as shown in Fig. 1.

The chuck part of the gauge comprises a solid polygonal block 24 shown,in this instance, as substantially square but as having its cornersformed on the internal radius of the casing I as indicated at 25 in Fig.5. The chuck block 24 has a tight or pressed t in the casing Il l andthe gauge piston in its normal position has the head 22 contacting withthe inner end of the block 24 as shown in Fig. 1r. The straight sides ofthe block 24 intermediate its curved corners 25 form with the casing I0longitudifnally extending air passages 26 as clearly indicated in Fig.5, t

The outer or lower end of the block 2.4, as viewed in the drawing,mounts centrally of the block an outwardly or downwardly extendingehnels pin 2l which can be integral with the block or separate therefromand secured there.- "l'lie ehnek part ef the. eenige .further eemprisesa felt washer 2B mounted on the pin 21 and engaging the lower end of theblock 24 and outwardly of the ielt washer 28 a washer 29 formedof'suitable material such as rubber either netntel er srnthetie..

` It will he understood `that when the gauge is appliedto a valve stemthe end of the stem will sealingly engag@ the washer `29 While the pin21 will engage the valve pin of the core or insides carried by the sternand depress the latter to open the valve of the insides or core. willallow air to flow from the stem around the pin 21 in the space 30 formedby the opening the washer 29 and thence through the felt Wahelf 23 andthe airpassages 26 to act on the lgauge piston to move the latteragainst the spring I9 and cause the gauge bar I5 to be moved outwardlyof the gauge to give a gauge rllgltleugll the Washers 23 and 29 may beienne@ in retiens Ways en advantageous wey 0f le e: these elements, Willnew be briefly de- The felt trein. Wnien the Washers 28 .Qrrned may beehteinesl in sheets. While the material constituting the washer 29 maybe inelsled. in sheets, Then. these sheets ef felt. and are. seenitedteeether by eernentine e1 @then suitable ent in.l strips., etiter; whichthe washers .28.. and 2e are uniterily blanked frein the. compositestripe.-

.l'tein the leeeeing description it Will.. be Seen that the sense. isestnernely simple. in. eQr-istruetion,H is y `vr`ined of relatively fewparts which can be easily en@ eeeneinieellr menuieetnred end embled, Itwill else be apparent that the gauge. can be so. inexpensively producedas to enable it .te be sold at. a, sunieientlr low price that it can beutilized as a novelty and advertising item for distribution to carowners. In addition, it will have been noted that the chuck part of thegauge is of novel construction and is such that it can be easily andeconomically manufactured and assembled in the gauge.

Although a preferred embodiment of the invention has been illustratedand described herein it will beunderstood that the invention issusceptible of various modifications and adaptations within the scope ofthe appended elaiin-Y Having thus described my invention, I claim:

In combination with an elongated tubular casing adapted to be used as anair gauge casing and to contain and slidably support a gauge bar forextension therefrom at one end of the casing and having a piston in saidcasing operatively associated with the gauge bar, a block mounted insaid casing adjacent the other end thereof and having surface portionsengaging said casing and Surface portions spaced from said easing andforming therewith air passages extending the length of said block andcommunicating with the interior of said casing, said block beingprovided with a centrally disposed pin on the end of the block towardsaid other end of the casingg a, per: forate washer on said end of theblock and surfrounding said pin, and a flexible washer on the enter side0f seid felt Washer and provided with en Opening through which said pinextends a clearance therebetween, said other en d of Sd Gesine beineCirculer in press section and said bleek being polygonal .in crosssection and haring its corners formed concentrieally to the interior ofsaid other end of said easing-l to tightly interi'lt the seme with apressed fit. While .its straightsides are spaced .from the inter-101.'of said casing and ferm therewith the. air passages. which extend thelength of the bloeit and place the. outer end of the block incommunieation with the interior ef the easing- HARRY W- REFERENCES CITEDThe following references are of record in the ille ofV this patent:

NITED- STATES

